MULTI-STEP PROCESS FOR PRODUCING INTERMEDIATE MOISTURE FOODS, AND ASSOCIATED SYSTEMS AND METHODS
Food processing methods and associated apparatuses are disclosed herein. In one embodiment, a food processing method includes heating a meat product in an oven to a pasteurizing temperature of the meat product followed by drying the meat product at the oven temperature that is below the maximum oven temperature of the processing cycle. In another embodiment, the method includes heating a meat product in a continuous belt grill, followed by drying the meat product in a temperature/relative humidity controlled oven. By breaking the food processing method into at least two phases, the method can result in a shorter processing time with better control of the process end points.
This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/545,077, filed on Oct. 7, 2011, and entitled “METHODS AND SYSTEMS FOR PRODUCING INTERMEDIATE MOISTURE FOODS,” the disclosure of which is incorporated herein by reference in its entirety.
TECHNICAL FIELDThe present technology generally relates to food processing. More particularly, several embodiments of the present technology relate to methods and systems for processing meats.
BACKGROUNDIt has been known in the food processing industry that reducing a moisture protein ratio to or below 0.75, reducing the water activity to or below 0.85, and pasteurizing the food (e.g., at least 160° F. internal temperature for beef) controls growth of bacterial pathogens of concern and comports with the USDA regulations. With vegetables, enzyme inactivation and pasteurization are achieved using a hot water blanching followed by subjecting the vegetables to a hot air process. With fruit, a sulfite treatment is used to inhibit both enzyme and microbe growth prior to the hot air drying.
In the food processing industry, the process of drying meats, fruits and vegetables is traditionally performed using hot air without humidity control. For example, beef jerky is processed using hot air in an oven to heat the food product and to reduce the moisture level of the product. The meat must be heated to an internal temperature of at least 160° F. to pasteurize the meat and remove sufficient moisture to achieve a target water activity level in the food product that inhibits microbial activity. In the traditional meat jerky manufacturing processes, only the temperature in the oven and the time to reach the minimum pasteurizing temperature are controlled. However, the target for the internal food temperature may be reached at a different time and/or be a different temperature than the ideal time and temperature for the target water activity of the food product. Furthermore, conventional processes typically increase the temperature gradually until the internal temperature of the food product reaches the target pasteurizing temperature. Although the conventional processes often stop heating when the maximum process temperature is reached, conventional processes typically have a cool-down period before handling the product (e.g., testing) to avoid exposing workers to the high temperatures of the food product. This is problematic because the food product continues to dry during the cool-down period, which makes it difficult to control the final water activity in the meat. As a result, if the cool-down period or other factors are not correct for a certain batch, the food product can be either too dry to be palatable or too moist to prevent microbial activity in the food product.
The present technology is generally directed toward food processing methods and associated apparatuses capable of producing dried food products, for example meat jerky. In particular, the present technology reduces processing times by separating a heating phase that rapidly reaches the required minimum pasteurization temperature of the food product and a drying phase that reduces the water activity at or below a target value for a given food product. By separating the process into at least two phases, the combined process time is reduced while the problems associated with conventional technologies are avoided. For example, a shorter heating phase can be achieved without excessive relative humidity that can result in water condensation on the surface of the food product. The drying phase can also be shortened by reducing the drying temperature in conjunction with reducing the relative humidity in the equipment, thus reducing the incidence of high temperature induced case hardening on the surface of the food product. Case hardening is a known process of creating a water impermeable skin on the food product, which, in turn, impedes drying of the product. The lower temperature and humidity of the drying phase also improves the uniformity of the drying. Additionally, having a lower end point temperature for the drying phase is safer and more comfortable for the operators who handle the food product at the end of the processing.
Specific details of certain embodiments of the technology are set forth in the following description and in
After or during the heating phase, the temperature of the product may be verified (block 25) to determine whether the pasteurization temperature of the product has been reached. Alternatively, the temperature and duration of the heating phase (block 20) can be selected such that the pasteurization temperature is achieved without verifying the food product temperature (block 25).
The illustrated embodiment of the inventive method further includes a drying phase (block 30). In at least some embodiments of the present technology, the drying phase starts after the pasteurizing temperature has been reached. It should be understood that some drying of the product may naturally occur during the heating phase (block 20) depending on the combination of temperature and relative humidity. For meat products such as jerky, the drying phase (block 30) may be terminated after the water activity decreases to about 0.85. In some embodiments of the present technology, the water activity of the food product can be verified (block 35) to assure that the required value has been reached before terminating the process. In other embodiments, a combination of drying time, temperature and relative humidity can be selected such that the target water activity is reached for a particular size and type of food product without verifying the water activity level. The food processing method 200 may finish (block 40) after the drying phase (block 30) and/or after verifying the water activity level.
As illustrated in
In the embodiment illustrated in
During the drying phase, the food products can be processed in conventional food processing equipment, such as the GCO oven made by FMC Food Technology of Sandusky, Ohio. During the drying phase, the temperature of the food product can be lowered below the pasteurization temperature while reducing the water activity of the food product to about 0.85. The combined processing time for the heating and drying phases of the food product can be about 37 minutes for some beef jerky food products.
The above Detailed Description of examples of the technology is not intended to be exhaustive or to limit the technology to the precise form disclosed above. For example, the heating phase can have a nonlinear temperature rise for faster heating without burning the skin of the food. Furthermore, in some embodiments a superheated steam can be used during the drying phase to shorten the drying process while reducing the risk of case hardening of the surface of the product. In some other embodiments, several pieces of processing equipment can be used for a given phase of the food product processing like, for example, the drying phase. Additionally, one or more transitional or intermediate phases can be added to the heating and drying phases and/or the heating and drying phases can have several sub-phases to shorten the time for reaching the pasteurization temperature and target water activity in the food product. A person of ordinary skill in the art will understand that many variations of the temperature, water activity and relative humidity can be used within the scope of the present inventive technology. Furthermore, some well-known structures or functions may not be shown or described in detail below, in order to emphasize the relevant parts of the invention description of the present technology. The terminology used below is to be interpreted in its broadest reasonable manner, even though it is being used in conjunction with a detailed description of certain specific examples of the present technology. Therefore, the actual scope of the invention encompasses not only the disclosed examples, but also all equivalent ways of practicing or implementing the invention under the claims.
Claims
1. A method for processing a meat product in at least one oven by controlling a temperature and a water activity of the meat product in a processing cycle, comprising:
- heating the meat product to at least a pasteurizing temperature of the meat product by increasing an oven temperature in a first temperature range having an upper temperature, wherein the water activity of the meat product remains above about 0.92; and
- after heating the meat product to at least the pasteurizing temperature, drying the meat product by decreasing the oven temperature below the upper temperature of the first temperature range, wherein the water activity of the meat product is reduced to below about 0.92.
2. The method of claim 1 wherein heating the meat product and drying the meat product are performed in different ovens.
3. The method of claim 1 wherein heating the meat product is performed while controlling a relative humidity in the oven.
4. The method of claim 1 wherein drying the meat product is performed while controlling a relative humidity in the oven.
5. The method of claim 1 wherein heating the meat product is performed in the oven having heated continuous belts.
6. The method of claim 5 wherein the meat product is in contact with at least one heated continuous belt.
7. The method of claim 5 wherein the meat product is in contact with at least two heated continuous belts.
8. The method of claim 5 wherein the temperature of the continuous belts is about 400° F. and wherein heating the meat product takes between 1 and 3 minutes.
9. The method of claim 1 wherein:
- heating the meat product is performed for about 60 minutes in the oven with— the temperature in the oven starting at about 40° F. wet bulb and ending at about 165° F. wet bulb, and a relative humidity in the oven starting at about 25% and ending at about 41%;
- drying the meat product is performed for about 90 minutes in the oven with— the temperature in the oven starting at about 165° F. wet bulb and ending at about 109° F. wet bulb, and the relative humidity in the oven starting at about 41% and ending at about 20%.
10. The method of claim 1 wherein:
- heating the meat product is performed for about 1 minute in a first oven at the temperature of about 400° F.;
- drying the meat product is performed in a second oven for about 30 minutes at the temperature ranging from about 218° F. wet bulb to 157° F. wet bulb while maintaining the relative humidity of the second oven between 60% and 15%.
11. The method of claim 9 wherein:
- during heating of the meat product, the temperature of the meat product is raised to about 165° F. within about 1 minute, and
- during drying of the meat product, the temperature of the meat product is lowered from about 165° F. to about 140° F. within about 30 minutes.
12. The method of claim 10 wherein heating of the meat product is performed in a first oven, and drying of the meat product is performed in a second oven different from the first oven.
13. The method of claim 12 wherein the first oven is a continuous belt grill.
14. The method of claim 1 wherein a superheated steam is used at least partially for drying the meat product.
15. The method of claim 1 wherein the humidity is increased to a heating humidity for at least a portion of the time while heating the meat product and the humidity is decreased from the heating humidity to a drying humidity while drying the meat product.
16. The method of claim 1 wherein the meat product is selected from a group consisting of beef, turkey, and chicken.
17. The method of claim 1, further comprising controlling the air velocity in at least one oven.
18. The method of claim 1, further comprising verifying the temperature of the meat product.
19. The method of claim 18 wherein verifying the temperature of the meat product is performed after the heating of the meat product.
20. The method of claim 1, further comprising verifying the water activity of the meat product.
21. The method of claim 20 wherein verifying the the water activity of the meat product is performed after the drying of the meat product.
22. A method for processing a meat product in at least one oven by controlling a temperature and a water activity of the meat product in a processing cycle, comprising:
- heating the meat product to at least a pasteurizing temperature of the meat product by increasing an oven temperature to a maximum oven temperature of a heating phase, wherein the water activity of the meat product remains above about 0.92; and
- after heating the meat product to at least the pasteurizing temperature, drying the meat product at an oven temperature below the maximum oven temperature of the heating phase, wherein the water activity of the meat product is reduced to below about 0.92.
Type: Application
Filed: Oct 8, 2012
Publication Date: Apr 11, 2013
Inventors: Richard Meyer (Kent, WA), Dina Price (Kent, WA)
Application Number: 13/647,282
International Classification: A23B 4/03 (20060101);